scientific method (inquiry). what is the scientific method….. the scientific method is a ______...
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Scientific Method (Inquiry)
What is the scientific method…..
?The scientific method is a ______
for answering questions.process
What is Science?
Here are a few statements to test your current
understanding of science!
Science actually attempts to disprove ideas (hypotheses).Science is limited strictly to solving problems about the physical and natural world.
Science can prove anything, solve any problem or answer any
question.True or False?
Any study done carefully and based on observation is scientific.
Science must follow certain rules. The rules of science make the scientific process as OBJECTIVE as is possible.
Objective = Not influenced by feelings, interests and prejudices; UNBIASED
Subjective = Influenced by feelings, interests and prejudices; BIASED
Different scientists may get different solutions to the same problem.
Understanding Experimental Design
A process of discovery…
The Controversy Over Spontaneous Generation
Question: What causes tiny living things to appear in decaying broth?
Needham’s Hypothesis: Spontaneous generation-Life forms arose from non-living matter.
Spallazani’s Hypothesis: Microbes come from the air. Boiling the broth will kill them.
Open flask >
Closed flask >
Experimental Designs with
Louis Pastuer …disproved the idea of spontaneous generation of life.
Louis Pasteur ended the debate with his famous swan-neck flask experiment, which allowed air to contact the broth. Microbes present in the dust were not able to navigate the winding bends in the neck of the flask.
Controlled all of the variables in the experiment--- GOOD EXPERIMENTAL DESIGN
Objectivity is the key to good science.and following standard procedures.
Soooo…what is good science?
Problem: Small Pox an infections disease of humans.• Infected human population dating from 10,000 B.C.E.• The disease killed an estimated 400,000 Europeans annually during the late
part of the 18th century.
• Those infected, 20–60%—and over 80% of infected children—died from the disease.
• Smallpox was responsible for an estimated 300–500 million deaths during
the 20th century.Solution: ????
The Beginnings of Immunology--using the scientific method
Edward Jenner and the first vaccine:
COWPOX : Infectious disease that caused mild discomfort, aching, a few pustules, some swelling…symptoms that disappeared in a few days.
SMALLPOX: Infectious disease that caused massive disfigurement, sometimes blindness, and often death.
Dr. Jenner was aware of farm workers' belief that if you had cowpox in the past, you wouldn’t get smallpox.
FYI- Last known case of Small Pox 1977.
The Beginnings of ImmunologyEdward Jenner and the first vaccine.
Question: Does having cowpox make a person immune to smallpox?
Hypothesis: If someone is infected with cowpox, then they will be immune to smallpox because having cowpox keeps a person from getting smallpox.
Experiment: Jenner made small incisions or punctures in arms of human subjects and rubbed in cowpox material (pus) in order to infect them with cowpox.
Analysis & Conclusion: He saw--- that people he had infected with cow pox, when later exposed to smallpox, would get a little bit sick, but never come down with a full-blown case of smallpox. Cowpox infection prevents smallpox infection.
Present Results / Peer Evaluation:At first his peers doubted the safety and value of his treatment, but eventually the importance of the cowpox inoculum was recognized.
1800’s – English physician
Vaccination was not without its critics. In this cartoon from 1802, the British satirist James Gillray implied that vaccination caused people
to become part cow.
• A series of steps that scientists use to answer questions and solve problems.
• Is not a rigid procedure. • Scientists may use all of the steps or just
some of the steps.• They may even repeat some of the steps. • The goal of the scientific method is to
come up with reliable answers and solutions to questions.
Scientific Method (Inquiry)Observation, Question or
• The scientific method starts with a question about something that is observed. (5 Senses)
• How, What, When, Who, Which, Why, or Where?
Research• Collect and
analyze information to increase your understanding of a topic or issue (question).
• A testable explanation for an answer to an observation, question or problem.
If _ [I do this]__ then _[this]__ will
• A procedure to test the hypothesis.
• An experimenter changes one factor and observes or measures what happens.
• The factor that is changed by the experimenter is known as the independent variable. (I do.)
• The factor that is measured or observed is called the dependent variable. (data)
A good or “valid” experiment will only have ONE independent variable!
The Independent variable is graphed on the ______________
The dependent variable is graphed on the _______________
The wall “depends” on the floor being there....
Constants• The experimenter makes a
special effort to control all the factors in an experiment so that they will not effect the outcome. (false results)
• These factors are called control variables or constants.
Controls are NOT being tested Controls are used for COMPARISON
Results or Data-Analysis
Data: Information collected during an experiment.
Analysis- Data is evaluated.
Tables and graphs are often used
to organize and analyze the data.
Discussion-based on the
analysis of the data.
Do the results support the
• Check for errors• Investigate again• Make a new hypothesis
• Results are verified by independent duplication and publication in a peer-reviewed journal
• Independent duplication = Two or more scientists from different institutions investigate the same question separately and get similar results.
• Peer-reviewed journal. = A journal that publishes articles only after they have been checked for quality by several expert, objective scientists from different institutions.
Scientific Theory vs. Law
Scientific Theory vs. Law
THEORYExplanation for an observation or
phenomena that is confirmed by a large amount of evidence or tests (experiments).
Germ theory of disease - Infectious diseases result from the action of microorganisms.
LAWA statement of a scientific principle
that appears to be without exception at the time it is made, and always works the same way under the
same conditions; A scientific rule. Example:
Newton's First Law of Motion (Law of Inertia) - every object either remains at rest or in continuous motion with constant speed unless acted upon by an outside force.
Treponema pallidum -
♪ (Trep-o-neemah pal-lid-um)
So, what's the difference?
A SCIENTIFIC THEORY
- are typically non-mathematical.
A SCIENTIFIC LAW
- are often mathematically defined
• Looking at things this way helps to explain, in part, why physics and chemistry have lots of "laws" whereas biology has few laws (and more theories).
• In biology, it is very difficult to describe all the complexities of life with "simple" (relatively speaking!) mathematical terms.